U.S. patent number 10,894,865 [Application Number 15/985,445] was granted by the patent office on 2021-01-19 for prepolymerized resin, preparation method thereof, resin composition comprising the same, and article made therefrom.
This patent grant is currently assigned to Elite Material Co., Ltd.. The grantee listed for this patent is Elite Material Co., Ltd.. Invention is credited to Shu-Hao Chang.
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United States Patent |
10,894,865 |
Chang |
January 19, 2021 |
Prepolymerized resin, preparation method thereof, resin composition
comprising the same, and article made therefrom
Abstract
A prepolymerized resin and a preparation method thereof are
provided, the method comprising a step of pre-reacting
bis(vinylphenyl)ethane and polybutadiene. Bis(vinylphenyl)ethane
may include 1,2-bis(4-vinylphenyl)ethane,
1,2-(3-vinylphenyl-4-vinylphenyl)ethane, 1,2-bis(3-vinylphenyl)
ethane or a combination thereof. Polybutadiene has a 1,2-vinyl
content of 85% or above and a number average molecular weight of
less than 3000. A resin composition comprising the prepolymerized
resin and an article made from the resin composition are also
provided.
Inventors: |
Chang; Shu-Hao (Taoyuan,
TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
Elite Material Co., Ltd. |
Taoyuan |
N/A |
TW |
|
|
Assignee: |
Elite Material Co., Ltd.
(Taoyuan, TW)
|
Appl.
No.: |
15/985,445 |
Filed: |
May 21, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190292326 A1 |
Sep 26, 2019 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 26, 2018 [TW] |
|
|
107110250 A |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G
81/022 (20130101); C08F 236/06 (20130101); C08F
12/34 (20130101); C08K 5/0025 (20130101); C08K
5/0066 (20130101); C08F 2/40 (20130101) |
Current International
Class: |
C08F
12/34 (20060101); C08F 236/06 (20060101); C08F
2/40 (20060101); C08G 81/02 (20060101); C08K
5/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Zemel; Irina S
Assistant Examiner: Lenihan; Jeffrey S
Attorney, Agent or Firm: Muncy, Geissler, Olds & Lowe,
P.C.
Claims
What is claimed is:
1. A method of preparing a prepolymerized resin, comprising
subjecting a composition to a pre-reaction in the presence of a
polymerization inhibitor, wherein the composition at least
comprises bis(vinylphenyl)ethane and polybutadiene, wherein the
polybutadiene has a 1,2-vinyl content of 85% or above and a number
average molecular weight of less than 3000, wherein the
pre-reaction has a conversion rate of between 30% and 90%, and
wherein, during the pre-reaction, components in the composition are
partially crosslinked to leave residual vinyl groups.
2. The method of claim 1, wherein the composition further comprises
vinyl-containing polyphenylene ether.
3. The method of claim 2, wherein the vinyl-containing
polyphenylene ether comprises vinylbenzyl-terminated polyphenylene
ether resin, vinylbenzyl-modified bisphenol A polyphenylene ether
resin, methacrylate-terminated polyphenylene ether resin,
vinyl-containing chain-extended polyphenylene ether resin or a
combination thereof.
4. The method of claim 1, wherein the polymerization inhibitor
comprises hydroquinone, p-benzoquinone, phenothiazine,
.beta.-phenylnaphthylamine, 4-t-butylcatechol, methylene blue,
4,4'-butylidenebis(6-t-butyl-3-methylphenol),
2,2'-methylenebis(4-ethyl-6-t-butylphenol) or a combination
thereof.
5. The method of claim 1, wherein peroxide is not used during the
pre-reaction.
6. The method of claim 1, wherein the polybutadiene has a number
average molecular weight of between 900 and 1,500.
7. A resin composition comprising a prepolymerized resin and an
additive, wherein the prepolymerized resin is prepared by
subjecting a composition to a pre-reaction in the presence of a
polymerization inhibitor, the composition at least comprising
bis(vinylphenyl)ethane and polybutadiene, wherein the polybutadiene
has a 1,2-vinyl content of 85% or above and a number average
molecular weight of less than 3000, wherein the pre-reaction has a
conversion rate of between 30% and 90%, and wherein, during the
pre-reaction, components in the composition are partially
crosslinked to leave residual vinyl groups; and wherein the
additive comprises polyphenylene ether, cyanate ester, maleimide
resin, polyolefin, acrylate, styrene, divinylbenzene,
bis(vinylbenzyl)ether, bis(vinylphenyl)ethane, triallyl
isocyanurate, triallyl cyanurate, 1,2,4-trivinyl cyclohexane or a
combination thereof.
8. The resin composition of claim 7, comprising 1 to 200 parts by
weight of the additive relative to 100 parts by weight of the
prepolymerized resin.
9. The resin composition of claim 7, further comprising epoxy
resin, phenolic resin, benzoxazine resin, styrene maleic anhydride,
acrylic acid, polyester, amine curing agent, diallyl bisphenol A,
polyamide, polyimide or a combination thereof.
10. The resin composition of claim 7, further comprising flame
retardant, inorganic filler, curing accelerator, solvent,
toughening agent, silane coupling agent or a combination
thereof.
11. An article made from the resin composition of claim 7,
comprising a resin film, a prepreg, a laminate or a printed circuit
board.
12. The article of claim 11, which has a surface not containing
branch-like pattern under visual inspection.
13. The article of claim 12, having a glass transition temperature
as measured by reference to IPC-TM-650 2.4.24.4 of greater than
190.degree. C. and a dissipation factor as measured by reference to
JIS C2565 of less than 0.0055.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefits of Taiwan Patent
Application No. 107110250, filed on Mar. 26, 2018. The entirety the
above-mentioned patent application is hereby incorporated by
reference herein and made a part of this specification.
BACKGROUND
1. Field of the Disclosure
Disclosed is a prepolymerized resin, a preparation method thereof,
a resin composition comprising the same, and an article made
therefrom.
2. Description of Related Art
Conventionally, polyphenylene ether resins are widely used for
making low dielectric copper-clad laminates, but copper-clad
laminates made solely from a polyphenylene ether resin has a low
glass transition temperature, and copper-free laminates made
therefrom have an unsatisfactory dissipation factor (Df) of greater
than 0.005 as measured under 10 GHz frequency, thereby failing to
meet the demands of new generation high frequency and low
dielectric circuit boards. While the addition of other components
in polyphenylene ether resins may increase the glass transition
temperature of copper-clad laminates and decrease the dissipation
factor, other problems arise in the meantime. For example, after
lamination, the laminates are prone to form branch-like pattern,
which deteriorates the reliability of circuit boards made from the
copper-clad laminates and significantly lowers the yield.
Accordingly, there is a need to develop a material for copper-clad
laminates that overcomes the aforesaid drawbacks.
SUMMARY
A primary object of this disclosure is to provide a prepolymerized
resin prepared by pre-reacting (i.e., via prepolymerization) a
composition, the composition at least comprising
bis(vinylphenyl)ethane and polybutadiene, wherein the polybutadiene
has a 1,2-vinyl content of 85% or above and a number average
molecular weight of less than 3000.
In one embodiment, the prepolymerized resin is prepared by
pre-reacting the composition in the presence of a polymerization
inhibitor.
In one embodiment, the composition further comprises
vinyl-containing polyphenylene ether.
In one embodiment, the prepolymerized resin has a number average
molecular weight of between 4,000 and 12,000.
In one embodiment, bis(vinylphenyl)ethane and polybutadiene are
prepolymerized according to a molar ratio of 9.9:0.1 to
0.1:9.9.
Preferably, bis(vinylphenyl)ethane and polybutadiene are
pre-reacted at a molar ratio of, for example, 9:1, 8:2, 7:3, 6:4,
5.5:4.5, 5:5, 4.5:5.5, 4:6, 3:7, 2:8 or 1:9, but not limited
thereto. For example, the molar ratio of bis(vinylphenyl)ethane to
polybutadiene may also be 2:1, 1:2, or 7.5:2.5.
According to the present disclosure, the prepolymerized resin
obtained from prepolymerizing bis(vinylphenyl)ethane and
polybutadiene is characterized by having a reactive vinyl group,
even after the prepolymerization process. Unless otherwise
specified, a vinyl or vinyl group used herein refers to a reactive
vinyl group.
The bis(vinylphenyl)ethane may be 1,2-bis(4-vinylphenyl)ethane,
1,2-(3-vinylphenyl-4-vinylphenyl)ethane,
1,2-(2-vinylphenyl-4-vinylphenyl)ethane,
1,2-bis(3-vinylphenyl)ethane,
1,2-(3-vinylphenyl-2-vinylphenyl)ethane,
1,2-bis(2-vinylphenyl)ethane or a combination thereof. More
preferred is 1,2-bis(4-vinylphenyl)ethane,
1,2-(3-vinylphenyl-4-vinylphenyl)ethane,
1,2-bis(3-vinylphenyl)ethane or a combination thereof.
1,2-bis(4-vinylphenyl)ethane has the structure shown below:
##STR00001##
As used herein, unless otherwise specified, "polybutadiene" refers
to a polybutadiene having a 1,2-vinyl content of 85% or above and a
number average molecular weight of less than 3000, examples
including but not limited to: a polybutadiene having a 1,2-vinyl
content of 85% or above and a number average molecular weight of
900 to 1500; a polybutadiene having a 1,2-vinyl content of 85% or
above and a number average molecular weight of 1000 to 1200; a
polybutadiene having a 1,2-vinyl content of 85% or above and a
number average molecular weight of about 1100; a polybutadiene
having a 1,2-vinyl content of 85% or above and a number average
molecular weight of 1800 to 2600; a polybutadiene having a
1,2-vinyl content of 85% or above and a number average molecular
weight of 2000 to 2200; and a polybutadiene having a 1,2-vinyl
content of 85% or above and a number average molecular weight of
about 2100. Preferably, a polybutadiene having a 1,2-vinyl content
of 85% or above and a number average molecular weight of less than
2000 is pre-reacted with bis(vinylphenyl)ethane.
Examples of polybutadiene used herein include B-1000 and B-2000
available from Nippon Soda Co., Ltd., or a combination thereof.
The polybutadiene used herein may have the structure shown
below:
##STR00002## wherein n=15 to 25, preferably n=16 to 22.
In one embodiment, the polybutadiene has a 1,2-vinyl content
(content of reactive vinyl group) of 85% or above and a 1,4-vinyl
content (content of non-reactive vinyl group) of 15% or below, and
the number average molecular weight is less than or equal to
2000.
More preferred is the polybutadiene having a 1,2-vinyl content of
85% or above, a 1,4-vinyl content of 15% or below and a number
average molecular weight of about 1100.
The prepolymerized resin of the present disclosure is prepared by
the prepolymerization of any bis(vinylphenyl)ethane as described
above and any polybutadiene as described above in the presence of a
polymerization inhibitor. In other words, the present disclosure
further relates to a method of preparing the aforesaid
prepolymerized resin, comprising: under a proper condition (e.g.,
in the presence of a polymerization inhibitor), subjecting a
composition to a pre-reaction, the composition at least comprising
bis(vinylphenyl)ethane and polybutadiene, wherein the polybutadiene
has a 1,2-vinyl content of 85% or above and a number average
molecular weight of less than 3000.
In the present disclosure, the use amount of polymerization
inhibitor is not particularly limited; relative to a total of one
mole of bis(vinylphenyl)ethane and polybutadiene, the amount of
polymerization inhibitor may range from 0.001 to 0.1 mole,
preferably from 0.005 to 0.05 mole.
The polymerization inhibitor may be an inhibitor for polymerization
and may comprise, without limitation: hydroquinone, p-benzoquinone,
phenothiazine, .beta.-phenylnaphthylamine, 4-t-butylcatechol,
methylene blue, 4,4'-butylidenebis(6-t-butyl-3-methylphenol),
2,2'-methylenebis(4-ethyl-6-t-butylphenol) or a combination
thereof.
Preferred polymerization inhibitor is
4,4'-butylidenebis(6-t-butyl-3-methylphenol) or
2,2'-methylenebis(4-ethyl-6-t-butylphenol).
One of the features of the present disclosure lies in controlling
the conversion rate of the pre-reaction between
bis(vinylphenyl)ethane and polybutadiene under proper conditions,
such as using the aforesaid polymerization inhibitor to control the
conversion rate of the pre-reaction between bis(vinylphenyl)ethane
and polybutadiene, such that they are partially crosslinked and
that the product thus formed retains residual vinyl groups. For
example, as used herein, pre-reaction may refer to a
prepolymerization reaction, and the conversion rate of the
pre-reaction is greater than 1% and less than 99%, preferably
greater than 10% and less than 90%. For example, during the
prepolymerization, the conversion rate of the pre-reaction between
bis(vinylphenyl)ethane and polybutadiene may be between 30% and
90%, preferably between 50% and 80%, and more preferably between
50% and 70%. Specifically, if the conversion rate of
bis(vinylphenyl)ethane and polybutadiene is 0%, there is completely
no reaction or crosslinking between bis(vinylphenyl)ethane and
polybutadiene, and the prepolymerized resin cannot be formed. In
contrast, a 100% conversion rate of bis(vinylphenyl)ethane and
polybutadiene indicates that bis(vinylphenyl)ethane and
polybutadiene have been fully crosslinked, therefore also failing
to form the prepolymerized resin, and the product thus obtained
does not contain any reactive vinyl group.
According to the method disclosed herein for preparing a
prepolymerized resin, a polymerization inhibitor is added during
polymerization to effectively control the conversion rate of
between 30% and 90%, preferably between 50% and 80%, and more
preferably between 50% and 70%.
One the other hand, if peroxide is added during polymerization, the
pre-reaction will be undesirably too fast, such that the conversion
rate cannot be controlled as below 100% or even below 90% easily,
making bis(vinylphenyl)ethane and polybutadiene completely
crosslinked without leaving any vinyl group. The absence of
residual vinyl group makes it difficult for the reaction product to
crosslink with other resins, and a 100% conversion rate of
bis(vinylphenyl)ethane and polybutadiene will result in an
unacceptably high viscosity of the product for impregnating
fiberglass fabrics. Accordingly, in one embodiment, peroxide is not
used during the pre-reaction for preparing prepolymerized
resin.
The prepolymerized resin disclosed herein has a number average
molecular weight of about 4000 to 12000, preferably 4000 to 10000,
and more preferably 4000 to 6000.
Also disclosed herein is another prepolymerized resin, which is
prepared by prepolymerizing bis(vinylphenyl)ethane, polybutadiene
and vinyl-containing polyphenylene ether, characterized by the
presence of reactive vinyl group after prepolymerization.
The aforesaid prepolymerized resin may also be formed in the
presence of a polymerization inhibitor, wherein the type and use
amount of the polymerization inhibitor are as described above.
The vinyl-containing polyphenylene ether is a vinyl-terminated
polyphenylene ether, wherein the capping vinyl group is the
reactive vinyl group described above. For example, unless otherwise
specified, the polyphenylene ether resin used herein is not
particularly limited and may comprise any one or more commercial
products, products synthesized by the applicant or a combination
thereof, such as but not limited to vinylbenzyl-terminated
polyphenylene ether resin (e.g., OPE-2st, available from Mitsubishi
Gas Chemical Co., Inc.), methacrylate-terminated polyphenylene
ether resin (e.g., SA-9000, available from SABIC),
vinylbenzyl-modified bisphenol A polyphenylene ether resin,
vinyl-containing chain-extended polyphenylene ether resin or a
combination thereof.
The vinyl-containing chain-extended polyphenylene ether resin may
include various polyphenylene ether resins disclosed in the US
Patent Application Publication No. 2016/0185904 A1, all of which
are incorporated herein by reference in their entirety.
Also disclosed herein is a method of preparing a prepolymerized
resin, comprising dissolving bis(vinylphenyl)ethane, polybutadiene
and a polymerization inhibitor in a solvent, rising the reaction
temperature to above room temperature, such as 30-80.degree. C. and
preferably 50-80.degree. C., and stirring the reaction for 0.5-3
hours and preferably 1-2 hours. Next, the temperature is lowered to
room temperature (about 25.degree. C.) to obtain a solution, which
is filtered to remove impurities to obtain a liquid state
pre-reaction product, i.e., the prepolymerized resin formed by
pre-reacting bis(vinylphenyl)ethane and polybutadiene.
Further disclosed herein is a method of preparing a prepolymerized
resin, comprising dissolving bis(vinylphenyl)ethane, polybutadiene
and a polymerization inhibitor in a solvent, followed by adding a
vinyl-containing polyphenylene ether, wherein the reaction is
stirred to dissolve the vinyl-containing polyphenylene ether if it
is in a solid state. Next, the reaction temperature is increased to
above room temperature, such as 30-80.degree. C., preferably
50-80.degree. C., and the reaction is stirred for 0.5-3 hours,
preferably 1-2 hours, and then the temperature is lowered to room
temperature (about 25.degree. C.) to obtain a solution, which is
filtered to remove impurities to obtain a liquid state pre-reaction
product, i.e., the prepolymerized resin formed by pre-reacting
vinyl-containing polyphenylene ether, bis(vinylphenyl)ethane and
polybutadiene.
In one embodiment, peroxide is not used during the pre-reaction for
preparing prepolymerized resin.
Also disclosed herein is a resin composition, comprising the
above-described prepolymerized resin and an additive.
The additive may be, for example, selected from a group consisting
of polyphenylene ether, cyanate ester, maleimide resin, polyolefin,
acrylate, styrene, divinylbenzene (DVB), bis(vinylbenzyl)ether
(BVBE), bis(vinylphenyl)ethane, triallyl isocyanurate (TAlC),
triallyl cyanurate (TAC), 1,2,4-trivinyl cyclohexane (TVCH) or a
combination thereof. Relative to 100 parts by weight of the
prepolymerized resin, individual additives or their combination may
be used by an amount of 1 to 200 parts by weight, preferably 5 to
100 parts by weight, more preferably 5 to 80 parts by weight, and
even more preferably 15 to 60 parts by weight. A preferred additive
is a vinyl-containing additive. Unless otherwise specified, a vinyl
or vinyl group described herein refers to a reactive vinyl
group.
Another object of the present disclosure is to provide an article
made from the resin composition, such as a resin film, a prepreg, a
laminate or a printed circuit board, but not limited thereto.
The article made from the resin composition may be a resin film,
which is prepared by heating and baking to cure the resin
composition. The resin composition may be selectively coated on a
polyethylene terephthalate film (PET film), a polyimide film (PI
film) or a copper foil, followed by heating and baking to semi-cure
the resin composition to Ruin the resin film.
The article made from the resin composition may be a prepreg, which
comprises a reinforcement material and a layered structure disposed
thereon. The layered structure is formed by heating the resin
composition at a high temperature to the B-stage. Suitable baking
temperature for making the prepreg may be for example 80.degree. C.
to 170.degree. C. For example, the reinforcement material may be
any one of a fiber material, woven fabric, non-woven fabric, liquid
crystal resin film, polyester (PET) film and polyimide (PI) film,
and the woven fabric preferably comprises fiberglass fabrics. Types
of fiberglass fabrics are not particularly limited and may be any
commercial fiberglass fabric useful for various printed circuit
boards, such as E-glass fabric, D-glass fabric, S-glass fabric,
T-glass fabric, L-glass fabric or NE-glass fabric, wherein the
fiber may comprise yarns and rovings, in spread form or standard
form. Non-woven fabric preferably comprises liquid crystal polymer
non-woven fabric, such as polyester non-woven fabric, polyurethane
non-woven fabric and so on, but not limited thereto. Woven fabric
may also comprise liquid crystal polymer woven fabric, such as
polyester woven fabric, polyurethane woven fabric and so on, but
not limited thereto. The reinforcement material may increase the
mechanical strength of the prepreg. In one preferred embodiment,
the reinforcement material can be optionally pre-treated by a
silane coupling agent. The prepreg may be further heated and cured
to the C-stage to form an insulation layer.
The article made from the resin composition may be a laminate,
which comprises two metal foils and an insulation layer (i.e., the
layered structure) disposed between the metal foils, wherein the
insulation layer is made by curing the resin composition at high
temperature and high pressure to the C-stage, a suitable curing
temperature being for example between 150.degree. C. and
220.degree. C. and preferably between 200.degree. C. and
210.degree. C. and a suitable curing time being 90 to 180 minutes
and preferably 120 to 150 minutes. The insulation layer may be the
aforesaid prepreg or resin film. The metal foil may comprise
copper, aluminum, nickel, platinum, silver, gold or alloy thereof,
such as a copper foil.
Preferably, the laminate is a copper-clad laminate (CCL).
The laminate may be further processed by trace formation processes
to provide a circuit board.
The prepolymerized resin disclosed herein is primarily
characterized by using a proper condition (e.g., presence of a
polymerization inhibitor) to inhibit or control the crosslinking
reaction between bis(vinylphenyl)ethane and polybutadiene and to
avoid undesirably fast reaction rate, thereby controlling a proper
conversion rate to form the prepolymerized resin. Several technical
advantages or effects have been achieved by the prepolymerized
resin prepared by using a proper condition (e.g., presence of a
polymerization inhibitor) to pre-react bis(vinylphenyl)ethane and
polybutadiene (having a 1,2-vinyl content of 85% or above and a
number average molecular weight of less than 3000), in contrast to
non-prepolymerized bis(vinylphenyl)ethane and polybutadiene, or a
composition containing peroxide prior to prepolymerization, or a
product made by prepolymerizing bis(vinylphenyl)ethane and
styrene-butadiene copolymer, or a product made by prepolymerizing
bis(vinylphenyl)ethane and an improper polybutadiene (e.g., having
a 1,2-vinyl content of less than 85%, or having a 1,2-vinyl content
of 85% or above and a number average molecular weight of above
3000), including: (1) the prepolymerized resin disclosed herein has
a vinyl group useful for crosslinking with other vinyl-containing
resin in a resin composition; (2) peroxide is not added during the
preparation of the prepolymerized resin, thereby avoiding a 100%
conversion rate of the prepolymerized resin and avoiding a
viscosity of the reaction product which is too high to impregnate
fiberglass fabrics; and (3) the copper-clad laminate made from the
prepolymerized resin disclosed herein has better dissipation
factor, copper foil peel strength, and interlayer bonding strength,
and after lamination, the laminate is free from branch-like
patterns.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the FTIR spectrum of prepolymerized resin A
according to the Preparation Example 1.
FIG. 2 illustrates the FTIR spectrum of
1,2-bis(4-vinylphenyl)ethane.
FIG. 3 illustrates the FTIR spectrum of polybutadiene (having a
1,2-vinyl content of 85% or above and a number average molecular
weight of less than 2000).
FIG. 4 illustrates a copper-free laminate having branch-like
pattern.
FIG. 5 illustrates a copper-free laminate not having branch-like
pattern.
DETAILED DESCRIPTION OF EMBODIMENTS
To enable those skilled in the art to further appreciate the
features and effects of the present disclosure, words and terms
contained in the specification and appended claims are described
and defined. Unless otherwise defined, all technical and scientific
terms used herein have the same meaning as commonly understood by
those of ordinary skill in the art to which this disclosure
pertains. In the case of conflict, the present document and
definitions contained herein will control.
While some theories or mechanisms may be proposed herein, the
present disclosure is not bound by any theories or mechanisms
described regardless of whether they are right or wrong, as long as
the embodiments can be implemented according to the present
disclosure.
As used herein, "a," "an" or similar expression is employed to
describe elements and features of the present disclosure. This is
done merely for convenience and to give a general sense of the
scope of the present disclosure. Accordingly, this description
should be read to include one or at least one and the singular also
includes the plural unless it is obvious to mean otherwise.
As used herein, the term "comprises," "comprising," "includes,"
"including," "has," "having" or any other variant thereof is
construed as an open-ended transitional phrase intended to cover a
non-exclusive inclusion. For example, a composition or article of
manufacture that comprises a list of elements is not necessarily
limited to only those elements but may include other elements not
expressly listed or inherent to such composition or article of
manufacture. Further, unless expressly stated to the contrary, the
term "or" refers to an inclusive or and not to an exclusive or. For
example, a condition "A or B" is satisfied by any one of the
following: A is true (or present) and B is false (or not present),
A is false (or not present) and B is true (or present), and both A
and B are true (or present). In addition, whenever open-ended
transitional phrases are used, such as "comprises," "comprising,"
"includes," "including," "has," "having" or any other variant
thereof, it is understood that transitional phrases such as
"consisting essentially of" and "consisting of" are also disclosed
and included.
In this disclosure, features such as values, numbers, contents,
amounts or concentrations presented as a numerical range or a
percentage range are merely for convenience and brevity. Therefore,
a numerical range or a percentage range should be interpreted as
encompassing and specifically disclosing all possible subranges and
individual numerals or values therein, particularly all integers
therein. For example, a range of "1 to 8" or "between 1 and 8"
should be understood as explicitly disclosing all subranges such as
1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8 and so on,
particularly all subranges defined by integers, as well as
disclosing individual values such as 1, 2, 3, 4, 5, 6, 7 and 8.
Unless otherwise defined, the aforesaid interpretation rule should
be applied throughout the present disclosure regardless broadness
of the scope.
Whenever amount, concentration or other numeral or parameter is
expressed as a range, a preferred range or a series of upper and
lower limits, it is understood that all ranges defined by any pair
of the upper limit or preferred value and the lower limit or
preferred value are specifically disclosed, regardless whether
these ranges are explicitly described or not. In addition, unless
otherwise defined, whenever a range is mentioned, the range should
be interpreted as inclusive of the endpoints and every integers and
fractions in the range.
Given the intended purposes and advantages of this disclosure are
achieved, numerals or figures have the precision of their
significant digits. For example, 40.0 should be understood as
covering a range of 39.50 to 40.49.
As used herein, a Markush group or a list of items is used to
describe examples or embodiments of the present disclosure. A
skilled artisan will appreciate that all subgroups of members or
items and individual members or items of the Markush group or list
can also be used to describe the present disclosure. For example,
when X is described as being "selected from a group consisting of
X.sub.1, X.sub.2 and X.sub.3," it is intended to disclose the
situations of X is X.sub.1 and X is X.sub.1 and/or X.sub.2. In
addition, when a Markush group or a list of items is used to
describe examples or embodiments of the present disclosure, a
skilled artisan will understand that any subgroup or any
combination of the members or items in the Markush group or list
may also be used to describe the present disclosure. Therefore,
when X is described as being "selected from a group consisting of
X.sub.1, X.sub.2 and X.sub.3" and Y is described as being "selected
from a group consisting of Y.sub.1, Y.sub.2 and Y.sub.3," the
disclosure encompasses any combination of X is X.sub.1 and/or
X.sub.2 and/or X.sub.3 and Y is Y.sub.1 and/or Y.sub.2 and/or
Y.sub.3.
Examples and embodiments are described in detail below. It will be
understood that these examples and embodiments are exemplary only
and are not intended to limit the scope of the present disclosure.
Unless otherwise specified, processes, reagents and conditions
described in the examples are those known in the art.
Disclosed herein is a prepolymerized resin prepared by pre-reacting
a composition, the composition at least comprising
bis(vinylphenyl)ethane and polybutadiene, wherein the polybutadiene
has a 1,2-vinyl content of 85% or above and a number average
molecular weight of less than 3000. In one embodiment, the
composition further comprises vinyl-containing polyphenylene
ether.
Also disclosed is a method of preparing the prepolymerized resin,
in which the composition is subject to prepolymerization under
proper conditions so that the product thus prepared contains
residual reactive vinyl group.
Also disclosed herein is a resin composition, comprising the
above-described prepolymerized resin and an additive.
Also disclosed herein is an article made from the resin
composition, comprising a resin film, a prepreg, a laminate or a
printed circuit board.
The resin composition disclosed herein comprises the aforesaid
prepolymerized resin and an additive, wherein the additive is
selected from a group consisting of polyphenylene ether, cyanate
ester, maleimide resin, polyolefin, acrylate, styrene,
divinylbenzene, bis(vinylbenzyl)ether, bis(vinylphenyl)ethane,
triallyl isocyanurate, triallyl cyanurate, 1,2,4-trivinyl
cyclohexane or a combination thereof.
Additives suitable for the resin composition disclosed herein are
described briefly below.
The polyphenylene ether may comprise a vinyl-containing
polyphenylene ether or a hydroxyl-containing polyphenylene ether.
For example, unless otherwise specified, the polyphenylene ether
used in the present disclosure is not particularly limited and may
be any commercial product, product synthesized by the applicant or
a combination thereof. Examples include, but not limited to,
dihydroxyl-terminated polyphenylene ether resin (e.g., SA-90
available from SABIC), vinylbenzyl-terminated polyphenylene ether
resin (e.g., OPE-2st available from Mitsubishi Gas Chemical Co.,
Inc.), methacrylate-terminated polyphenylene ether resin (e.g.,
SA-9000 available from SABIC), vinylbenzyl-modified bisphenol A
polyphenylene ether resin, vinyl-containing chain-extended
polyphenylene ether resin or a combination thereof. A preferred
polyphenylene ether is the vinyl-containing polyphenylene
ether.
The cyanate ester may include any one or more cyanate ester resins
useful for preparing a prepreg, a resin film, a laminate or a
printed circuit board, such as a compound having an
Ar--O--C.ident.N structure, wherein Ar may be a substituted or
unsubstituted aromatic group. Examples include but are not limited
to novolac cyanate ester resin, bisphenol A cyanate ester resin,
bisphenol F cyanate ester resin, dicyclopentadiene-containing
cyanate ester resin, naphthalene-containing cyanate ester resin,
phenolphthalein cyanate ester resin, adamantane cyanate ester resin
or fluorene cyanate ester resin. The novolac cyanate ester resin
may be bisphenol A novolac cyanate ester resin, bisphenol F novolac
cyanate ester resin or a combination thereof. For example, the
cyanate ester resin may be available under the tradename Primaset
PT-15, PT-30S, PT-60S, CT-90, BADCY, BA-100-10T, BA-200, BA-230S,
BA-300S, BTP-2500, BTP-6020S, DT-4000, DT-7000, Methylcy, and
ME-240S sold by Lonza.
The maleimide resin refers to a compound, monomer, mixture,
oligomer or polymer containing at least one maleimide group. Unless
otherwise specified, the maleimide resin used in the present
disclosure is not particularly limited and may include any one or
more maleimide resins useful for preparing a prepreg, a resin film,
a laminate or a printed circuit board. Examples include but are not
limited to 4,4'-diphenylmethane bismaleimide, oligomer of
phenylmethane maleimide (a.k.a. polyphenylmethane maleimide),
m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide,
3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide,
4-methyl-1,3-phenylene bismaleimide,
1,6-bismaleimide-(2,2,4-trimethyl hexane), N-2,3-xylylmaleimide,
N-2,6-xylenemaleimide, N-phenylmaleimide, maleimide compound
containing aliphatic long chain structure, prepolymer thereof and a
combination thereof. The aforesaid prepolymer may for example be a
prepolymer of diallyl compound and maleimide compound, a prepolymer
of diamine and maleimide compound, a prepolymer of multi-functional
amine and maleimide compound or a prepolymer of acid phenol
compound and maleimide compound
For example, the maleimide resin may include products such as
BMI-70, BMI-80, BMI-1000, BMI-1000H, BMI-1100, BMI-1100H, BMI-2000,
BMI-2300, BMI-3000, BMI-3000H, BMI-4000H, BMI-5000, BMI-5100,
BMI-7000 and BMI-7000H sold by Daiwa Kasei Co., Ltd.
For example, the maleimide resin containing aliphatic long chain
structure may include products such as BMI-689, BMI-1400, BMI-1500,
BMI-1700, BMI-2500, BMI-3000, BMI-5000 and BMI-6000 sold by
Designer Molecules Inc.
In one embodiment, the content of maleimide resin is 10 to 80 and
preferably 20 to 70 parts by weight relative to 100 parts by weight
of the prepolymerized resin.
The acrylate may include, but not limited to, tricyclodecane
di(meth)acrylate, tri(meth)acrylate,
1,1'-[(octahydro-4,7-methano-1H-indene-5,6-diyl)bis(methylene)]ester
(e.g., SR833S, available from Cray Valley) or a combination
thereof.
Examples of polyolefin include but are not limited to
styrene-butadiene-divinylbenzene terpolymer,
styrene-butadiene-maleic anhydride terpolymer,
vinyl-polybutadiene-urethane oligomer, styrene butadiene copolymer,
hydrogenated styrene butadiene copolymer, styrene isoprene
copolymer, hydrogenated styrene isoprene copolymer, hydrogenated
styrene-butadiene-divinylbenzene copolymer, polybutadiene
(homopolymer of butadiene), maleic anhydride-styrene-butadiene
copolymer, methyl styrene copolymer or a combination thereof.
In addition to the aforesaid components, the resin composition may
further comprise epoxy resin, phenolic resin, benzoxazine resin,
styrene maleic anhydride, acrylic acid, polyester, amine curing
agent, diallyl bisphenol A, polyamide, polyimide or a combination
thereof.
The resin composition may further comprise flame retardant,
inorganic filler, curing accelerator, solvent, toughening agent,
silane coupling agent or a combination thereof.
The flame retardant used herein may be any one or more flame
retardants useful for preparing a prepreg, a resin film, a laminate
or a printed circuit board; examples of flame retardant include but
are not limited to phosphorus-containing flame retardant, which
comprises ammonium polyphosphate, hydroquinone bis-(diphenyl
phosphate), bisphenol A bis-(diphenylphosphate),
tri(2-carboxyethyl) phosphine (TCEP), phosphoric acid
tris(chloroisopropyl) ester, trimethyl phosphate (TMP), dimethyl
methyl phosphonate (DMMP), resorcinol bis(dixylenyl phosphate)
(RDXP, such as commercially available PX-200, PX-201, and PX-202),
phosphazene (such as commercially available SPB-100, SPH-100, and
SPV-100), melamine polyphosphate, DOPO and its derivatives or
resins, DPPO (diphenylphosphine oxide) and its derivatives or
resins, melamine cyanurate, tri-hydroxy ethyl isocyanurate,
aluminium phosphinate (e.g., commercially available OP-930 and
OP-935) or a combination thereof.
For example, the flame retardant may be a DPPO compound (e.g.,
bis-DPPO compound), a DOPO compound (e.g., bis-DOPO compound), a
DOPO resin (e.g., DOPO-HQ, DOPO-NQ, DOPO-PN, and DOPO-BPN) and a
DOPO-containing epoxy resin, wherein DOPO-PN is a DOPO phenol
novolac compound, and DOPO-BPN may be a bisphenol novolac compound,
such as DOPO-BPAN (DOPO-bisphenol A novolac), DOPO-BPFN
(DOPO-bisphenol F novolac) and DOPO-BPSN (DOPO-bisphenol S
novolac).
For example, relative to a total of 100 parts by weight of the
prepolymerized resin and the additive, the amount of flame
retardant used in the present disclosure is not particularly
limited, and may range from 1 to 100 parts by weight, such as 10 to
90 parts by weight, 20 to 80 parts by weight, 30 to 70 parts by
weight, or 40 to 60 parts by weight.
The inorganic filler may be any one or more inorganic fillers
useful for preparing a prepreg, a resin film, a laminate or a
printed circuit board; examples of inorganic filler include but are
not limited to silica (fused, non-fused, porous or hollow type),
aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium
hydroxide, calcium carbonate, aluminum nitride, boron nitride,
aluminum silicon carbide, silicon carbide, titanium dioxide, zinc
oxide, zirconium oxide, mica, boehmite (AlOOH), calcined talc,
talc, silicon nitride and calcined kaolin. Moreover, the inorganic
filler can be spherical, fibrous, plate-like, particulate,
sheet-like or whisker-like in shape and can be optionally
pretreated by a silane coupling agent.
For example, the curing accelerator (including curing initiator)
may comprise a catalyst, such as a Lewis base or a Lewis acid. The
Lewis base may comprise any one or more of imidazole, boron
trifluoride-amine complex, ethyltriphenyl phosphonium chloride,
2-methylimidazole (2MI), 2-phenyl-1H-imidazole (2PZ),
2-ethyl-4-methylimidazole (2E4MI), triphenylphosphine (TPP) and
4-dimethylaminopyridine (DMAP). The Lewis acid may comprise metal
salt compounds, such as those of manganese, iron, cobalt, nickel,
copper and zinc, such as zinc octanoate or cobalt octanoate. The
curing accelerator also includes a curing initiator, such as a
peroxide capable of producing free radicals, examples of curing
initiator including but not limited to dicumyl peroxide, tert-butyl
peroxybenzoate, dibenzoyl peroxide (BPO),
2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne (25B),
bis(tert-butylperoxyisopropyl)benzene or a combination thereof.
The purpose of adding solvent is to change the solid content of the
resin composition and to adjust the viscosity of the resin
composition. For example, the solvent may comprise, but not limited
to, methanol, ethanol, ethylene glycol monomethyl ether, acetone,
butanone (methyl ethyl ketone), methyl isobutyl ketone,
cyclohexanone, toluene, xylene, methoxyethyl acetate, ethoxyethyl
acetate, propoxyethyl acetate, ethyl acetate, dimethylformamide,
dimethylacetamide, propylene glycol methyl ether, or a mixture
thereof.
Silane coupling agent may comprise silane (such as but not limited
to siloxane) and may be further categorized according to the
functional groups into amino silane, epoxide silane, vinyl silane,
acrylate silane, methacrylate silane, hydroxyl silane, isocyanate
silane, methacryloxy silane and acryloxy silane.
The purpose of adding toughening agent is to improve the toughness
of the resin composition. The toughening agent may comprise, but
not limited to, rubber resin, carboxyl-terminated butadiene
acrylonitrile rubber (CTBN rubber), core-shell rubber, or a
combination thereof.
The names of chemicals used in the examples and comparative
examples are as follows. H1: SA-9000, methacrylate-terminated
polyphenylene ether resin, available from SABIC; H2: OPE-2st 2200,
vinylbenzyl-terminated polyphenylene ether resin, available from
Mitsubishi Gas Chemical Co., Inc.; H3: Topas COC 5013, cycloolefin
copolymer not containing a reactive functional group, available
from Topas Advanced Polymers; H4: 1,2-bis(4-vinylphenyl)ethane,
available from Linchuan Chemical Co., Ltd.; H5: B-1000,
polybutadiene with a 1,2-vinyl content of 85% or above and a number
average molecular weight Mn of about 2000 or less, available from
Nippon Soda Co., Ltd.; H6: Ricon 150, polybutadiene with a
1,2-vinyl content of 70% and a number average molecular weight Mn
of about 3900; H8: dicumyl peroxide, available from NOF
Corporation; H9: SC-2500 SVJ, spherical silica, available from
Admatechs; and H10: commercially available toluene.
Preparation Example 1
0.2 mole of polybutadiene (having a 1,2-vinyl content of 85% or
above and a number average molecular weight of less than 2000), 0.1
mole of 1,2-bis(4-vinylphenyl)ethane and 1000 mL of toluene were
added to a reactor. The reaction temperature was increased to
60.degree. C., and the reaction was stirred to dissolve starting
materials into toluene. Then 0.005 mole of
2,2'-methylenebis(4-ethyl-6-t-butylphenol) was added, followed by
stirring at 60.degree. C. for 1 hour. The temperature was lowered
to room temperature (about 25.degree. C.), and the solution was
filtered to remove impurities to obtain a solution of
prepolymerized resin A, which is the prepolymerized resin according
to the present disclosure.
The prepolymerized resin A (prepolymer A) was analyzed by using
Fourier transform infrared spectroscopy (FTIR), with the result
shown in FIG. 1. In FIG. 1, 1418, 1449, and 1512 cm.sup.-1 are
absorptions of benzene ring, and 1640 cm.sup.-1 is the absorption
of C.dbd.C stretch of residual side chain 1,2-vinyl group in the
polybutadiene after pre-reaction.
FIG. 2 illustrates the FTIR spectrum of
1,2-bis(4-vinylphenyl)ethane. In FIG. 2, 1628 cm.sup.-1 represents
the absorption of C.dbd.C stretch of terminal vinyl group on
benzene ring, and 1403, 1452, 1508 cm.sup.-1 are absorptions of
benzene ring.
FIG. 3 illustrates the FTIR spectrum of polybutadiene (having a
1,2-vinyl content of 85% or above and a number average molecular
weight of less than 2000). In FIG. 3, 1640 cm.sup.-1 represents the
absorption of C.dbd.C stretch of side chain 1,2-vinyl group.
Comparison of FIG. 1 through FIG. 3 indicates that the absorption
intensity of the C.dbd.C stretch of terminal vinyl group on benzene
ring of 1,2-bis(4-vinylphenyl)ethane and the absorption intensity
of C.dbd.C stretch of side chain 1,2-vinyl group of polybutadiene
are both significantly reduced, showing that in Preparation Example
1, vinyl groups in 1,2-bis(4-vinylphenyl)ethane and polybutadiene
were partially crosslinked to faun the prepolymerized resin A.
Preparation Example 2
The operation was substantially the same as Preparation Example 1,
except that 2,2'-methylenebis(4-ethyl-6-t-butylphenol) was replaced
by hydroquinone, and a solution of prepolymerized resin B was
obtained, which is the prepolymerized resin according to the
present disclosure.
Preparation Example 3
The operation was substantially the same as Preparation Example 1,
except that the reaction temperature was increased to 70.degree.
C., under which the reaction was stirred for 40 minutes, and a
solution of prepolymerized resin C was obtained, which is the
prepolymerized resin according to the present disclosure.
Preparation Example 4
The operation was substantially the same as Preparation Example 1,
except that no polymerization inhibitor was added, and a solution
of prepolymerized resin D was obtained.
Preparation Example 5
The operation was substantially the same as Preparation Example 1,
except that the same amount of dicumyl peroxide was used in place
of 2,2'-methylenebis(4-ethyl-6-t-butylphenol), and a solution of
prepolymerized resin E was obtained.
Preparation Example 6
The operation was substantially the same as Preparation Example 1,
except that 0.1 mole of polybutadiene (having a 1,2-vinyl content
of 85% or above and a number average molecular weight of less than
2000), 0.2 mole of 1,2-bis(4-vinylphenyl)ethane, 1 mole of
vinylbenzyl-terminated polyphenylene ether (OPE-2st 2200) and 1000
mL of toluene were added to the reactor, and a solution of
prepolymerized resin F-1 was obtained, which is the prepolymerized
resin according to the present disclosure.
Preparation Example 7
The operation was substantially the same as Preparation Example 6,
except that vinylbenzyl-terminated polyphenylene ether (OPE-2st)
was replaced by the same amount of methacrylate-terminated
polyphenylene ether (SA-9000), and a solution of prepolymerized
resin F-2 was obtained, which is the prepolymerized resin according
to the present disclosure.
Preparation Example 8
The operation was substantially the same as Preparation Example 1,
except that 0.1 mole of polybutadiene (having a 1,2-vinyl content
of 85% or above and a number average molecular weight of less than
2000) was used, and a solution of prepolymerized resin G-1 was
obtained, which is the prepolymerized resin according to the
present disclosure.
Preparation Example 9
The operation was substantially the same as Preparation Example 1,
except that 0.1 mole of polybutadiene (having a 1,2-vinyl content
of 85% or above and a number average molecular weight of less than
2000) and 0.2 mole of 1,2-bis(4-vinylphenyl)ethane were
pre-reacted, and a solution of prepolymerized resin G-2 was
obtained, which is the prepolymerized resin according to the
present disclosure.
Preparation Example 10
The operation was substantially the same as Preparation Example 9,
except that the polybutadiene (having a 1,2-vinyl content of 85% or
above and a number average molecular weight of less than 2000) was
replaced by another polybutadiene (Ricon 150, having a 1,2-vinyl
content of 70% and a number average molecular weight of about
3900), and a solution of prepolymerized resin G-3 was obtained.
Preparation Example 11
The operation was substantially the same as Preparation Example 10,
except that the polybutadiene (having a 1,2-vinyl content of 85% or
above and a number average molecular weight of less than 2000) was
replaced by butadiene styrene copolymer (Ricon 100, having a
1,2-vinyl content of 70% and a number average molecular weight of
about 4500), and a solution of prepolymerized resin G-4 was
obtained.
The differences of prepolymerized resin A, prepolymerized resin D
and prepolymerized resin E can be observed below.
TABLE-US-00001 Prepolymerized Result of Fiberglass Resin Conversion
Rate Resin Viscosity Fabric Impregnation A under control acceptable
flat and smooth E above 95% high unable to impregnate D above 70%
and high high viscosity and high not flat and smooth, and variation
between variation between branch-like pattern batches batches
formed
Results of Examples and Comparative Examples are listed in Table 1
to Table 2 below, in which the amount of each component is
expressed as part by weight.
Resin compositions from different Examples (E1 to E10) and
Comparative Examples (C1 to C6) listed in Table 1 and Table 2 were
respectively added to a stirred tank, well mixed and fully
dissolved as varnishes and then added to an impregnation tank. A
fiberglass fabric (e.g., 2116 or 1080 E-glass fiber fabric) was
passed through the impregnation tank to adhere the resin
composition on the fiberglass fabric, followed by heating at
120.degree. C. to 170.degree. C. to the semi-cured state (B-Stage)
to obtain the prepreg.
Test samples or specimens were prepared as follows.
1. Copper-Clad Laminate (Obtained by Laminating Five Prepregs)
Two 18 jam hyper very low profile (HVLP) copper foils and five
prepregs made from each resin composition (using 2116 E-glass fiber
fabrics) were prepared. Each prepreg has a resin content of about
55%. A copper foil, five prepregs and a copper foil were
superimposed in such order and then subject to a vacuum condition
for lamination at 195.degree. C. for 2 hours to form each
copper-clad laminate sample. Insulation layers were formed by
curing (C-stage) five sheets of superimposed prepreg between the
two copper foils, and the resin content of the insulation layers is
about 55%.
2. Copper-Free Laminate (Obtained by Laminating Five Prepregs)
Each copper-clad laminate was etched to remove the two copper foils
to obtain a copper-free laminate made from laminating five prepregs
and having a resin content of about 55%.
3. Copper-Free Laminate (Obtained by Laminating Two Prepregs)
Two 18 .mu.m hyper very low profile (HVLP) copper foils and two
prepregs made from each resin composition (using 1080 E-glass fiber
fabrics) were prepared. Each prepreg has a resin content of about
70%. A copper foil, two prepregs and a copper foil were
superimposed in such order and then subject to a vacuum condition
for lamination at 195.degree. C. for 2 hours to form each
copper-clad laminate sample. Next, each copper-clad laminate was
etched to remove the two copper foils to obtain a copper-free
laminate made from laminating two prepregs and having a resin
content of about 70%.
Test items and test methods are described below.
1. Glass Transition Temperature (Tg)
The copper-free laminate (obtained by laminating five prepregs)
sample was subject to glass transition temperature measurement. The
glass transition temperature of each sample was measured using
dynamic mechanical analysis (DMA) method by reference to IPC-TM-650
2.4.24.4, and higher glass transition temperature (.degree. C.) is
better.
2. Dissipation Factor (Df)
The copper-free laminate (obtained by laminating two prepregs)
sample was subject to dissipation factor measurement. Each sample
was measured by using a microwave dielectrometer (available from
AET Corp.) by reference to JIS C2565 at room temperature (about
25.degree. C.) and under 10 GHz frequency. Lower dissipation factor
represents better dielectric properties of the sample. Under a 10
GHz frequency, for a Df value of less than 0.005, a difference in
Df of less than 0.0001 represents no substantial difference in
dissipation factor in different laminates, and a difference in Df
value of greater than 0.0001 represents a significant difference
(i.e., significant technical difficulty) in dissipation factor in
different laminates.
3. Copper Foil Peeling Strength (P/S)
The copper-clad laminate (obtained by laminating five prepregs) was
cut into a rectangular specimen with a width of 24 mm and a length
of greater than 60 mm, which was etched to remove surface copper
foil and leaving a rectangular copper foil with a width of 3.18 mm
and a length of greater than 60 mm, and tested by using a tensile
strength tester by reference to IPC-TM-650 2.4.8 at room
temperature (about 25.degree. C.) to measure the force (lb/in)
required to separate the copper foil from the insulation layer.
Under a 10 GHz frequency, for a copper-clad laminate with a Df
value of less than 0.005, a difference in peeling strength of
greater than 0.1 lb/in represents a significant difference.
4. Interlayer Bonding Strength (B/S)
The copper-clad laminate (obtained by laminating five prepregs) was
cut into a rectangular specimen with a width of 12.7 mm and a
length of greater than 60 mm and tested by using a tensile strength
tester by reference to IPC-TM-650 2.4.8. With the proviso that the
surface copper foil was not etched off and the measurement position
was set at the interface between the second prepreg layer and the
third prepreg layer, at room temperature (about 25.degree. C.), the
cured insulation laminate was tested to measure the force (lb/in)
required to separate the two layers. Under a 10 GHz frequency, for
a copper-clad laminate with a Df value of less than 0.005, a
difference in interlayer bonding strength of greater than 0.1 lb/in
represents a significant difference.
5. Thermal Resistance After Moisture Absorption (PCT)
The copper-free laminate specimen (obtained by laminating five
prepregs) was subject to pressure cooking test (PCT) by reference
to IPC-TM-650 2.6.16.1 and 5 hours of moisture absorption (test
temperature 121.degree. C., relative humidity 100%), and then by
reference to IPC-TM-650 2.4.23, the copper-free laminate specimen
after moisture absorption was immersed into a 288.degree. C. solder
bath for 20 seconds, removed and inspected for the presence of
delamination or blistering, which represents "fail", such as
whether interlayer delamination or blistering occurs between
insulation layers. Interlayer delamination or blistering may occur
between any layers of the laminate.
6. Resin Flow of Prepreg During Lamination (Resin Flow)
During the preparation of the copper-clad laminate (obtained by
laminating five prepregs), a copper foil, five prepregs and a
copper foil were superimposed in such order and then subject to a
vacuum condition for lamination at 195.degree. C. for 2 hours to
form each copper-clad laminate sample, which was then subject to
etching process to remove the copper foils on both sides to obtain
the copper-free laminate. Resin flow at edge of the copper-free
laminate was examined with naked eyes, wherein the cured portion of
resin flow beyond the edge of the prepreg was measured by a ruler
for the vertical distance (mm) from the edge of the prepreg. The
presence of weave exposure of 1.times.1 cm.sup.2 on the surface of
copper-free laminate is determined as dry board. As understood by a
skilled person in this field, dry board means that the laminate is
not suitable for subsequent processes for making a multi-layer
board or a circuit board.
7. Branch-Like Pattern Formation at Laminate Edge After Lamination
(Branch-like Pattern)
During the preparation of the copper-clad laminate (obtained by
laminating five prepregs), a copper foil, five prepregs and a
copper foil were superimposed in such order and then subject to a
vacuum condition for lamination at 195.degree. C. for 2 hours to
form each copper-clad laminate sample, which was then subject to
etching process to remove the copper foils on both sides to obtain
the copper-free laminate. The surface of the insulation layer of
the copper-free laminate was examined with naked eyes to determine
whether branch-like pattern was formed at the edge, which
represents poor compatibility of the resin composition or high
flowability variation that causes inhomogeneity. Presence of
branch-like pattern will cause several drawbacks including
inconsistent properties (poor reliability) of circuit boards made
therefrom and significantly lowered yield, such as poor dielectric
properties, low thermal resistance, inconsistent thermal expansion
or poor interlayer adhesion. FIG. 4 illustrates a copper-free
laminate having branch-like pattern, and FIG. 5 illustrates a
copper-free laminate not having branch-like pattern.
TABLE-US-00002 TABLE 1 Composition E1 E2 E3 E4 E5 E6 E7 E8 H1 100
100 100 100 100 100 70 H2 30 H3 G-2 30 60 15 75 30 G-1 30 A 30 F-1
130 G-3 G-4 H4 H5 H6 H8 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 H9 50 50 50
50 50 50 50 50 H10 100 100 100 100 100 100 100 100 Property E1 E2
E3 E4 E5 E6 E7 E8 Tg 227 235 220 222 218 239 228 230 Df 0.0042
0.0042 0.0043 0.0043 0.0042 0.0042 0.0043 0.0043 P/S 4.3 3.9 4.2
4.2 4.2 3.7 4.0 4.0 B/S 3.5 3.2 3.4 3.3 3.3 3.2 3.2 3.1 PCT pass
pass pass pass pass fail pass pass Resin flow 3~5 2~3 3~5 3~5 3~6
2~3 2~3 1~2 Branch-like no no no no no no no no pattern
TABLE-US-00003 TABLE 2 Composition E9 E10 C1 C2 C3 C4 C5 C6 H1 25
100 100 100 100 100 H2 75 100 H3 100 G-2 24 30 G-1 3 A 3 F-1 G-3 30
G-4 30 H4 20 20 20 H5 10 10 H6 10 H8 0.2 0.2 0.2 0.2 0.2 0.2 0.2
0.2 H9 20 50 50 50 50 50 50 50 H10 100 100 100 100 100 100 100 100
Property E9 E10 C1 C2 C3 C4 C5 C6 Tg 236 227 220 225 227 228 186
229 Df 0.0042 0.0042 0.0045 0.0042 0.0047 0.0046 0.0058 0.0046 P/S
4.5 3.1 3.2 3.5 3.8 3.5 3.9 3.9 B/S 3.5 2.4 2.8 3.0 3.2 3.2 3.2 2.4
PCT pass fail pass pass pass pass pass pass Resin flow 2~3 0 (dry
board) <1 3~5 3~5 2~3 3~5 <1 Branch-like no no yes yes yes
yes no yes pattern
The following observations can be made from the results in Table 1
and Table 2.
Compared with C3 (not containing prepolymerized resin but using
individual polybutadiene with a 1,2-vinyl content of 85% or above
and a number average molecular weight of less than 2000 and
bis(vinylphenyl)ethane) and compared with C4 (not containing
prepolymerized resin but using individual polybutadiene with a
1,2-vinyl content of 70% and a number average molecular weight of
about 3900 and bis(vinylphenyl)ethane), E1 (containing
prepolymerized resin) demonstrates better dissipation factor,
better peeling strength and better interlayer bonding strength and
does not form branch-like pattern.
Compared with C1 (containing prepolymerized resin of polybutadiene
with a 1,2-vinyl content of 70% and a number average molecular
weight of about 3900 and bis(vinylphenyl)ethane) and C2 (containing
prepolymerized resin of butadiene styrene copolymer with a
1,2-vinyl content of 70% and a number average molecular weight of
about 4500 and bis(vinylphenyl)ethane), E1 demonstrates better
peeling strength and better interlayer bonding strength and does
not form branch-like pattern.
Compared with C5 (containing only vinyl-containing polyphenylene
ether and no other resin), C3 and C4 have higher glass transition
temperature and improved dissipation factor, but the edge of
laminate obtained therefrom forms branch-like pattern.
Compared with C6 (not containing prepolymerized resin but using
individual polybutadiene with a 1,2-vinyl content of 85% or above
and a number average molecular weight of less than 2000,
bis(vinylphenyl)ethane and vinyl-containing polyphenylene ether),
E8 (containing prepolymerized resin of polybutadiene with a
1,2-vinyl content of 85% or above and a number average molecular
weight of less than 2000, bis(vinylphenyl)ethane and
vinyl-containing polyphenylene ether) demonstrates better
dissipation factor and better interlayer bonding strength and does
not form branch-like pattern.
The above detailed description is merely illustrative in nature and
is not intended to limit the embodiments of the subject matter or
the application and uses of such embodiments. As used herein, the
term "exemplary" or "example" means "serving as an example,
instance, or illustration." Any implementation described herein as
exemplary is not necessarily to be construed as preferred or
advantageous over other implementations, unless otherwise
specified.
Moreover, while at least one exemplary example or comparative
example has been presented in the foregoing detailed description,
it should be appreciated that a vast number of variations exist. It
should also be appreciated that the exemplary one or more
embodiments described herein are not intended to limit the scope,
applicability, or configuration of the claimed subject matter in
any way. Rather, the foregoing detailed description will provide
those skilled in the art with a convenient guide for implementing
the described one or more embodiments. Also, the scope defined by
the claims includes known equivalents and foreseeable equivalents
at the time of filing this patent application.
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